Secondary syphilis of the floor of the mouth masquerading as squamous cell carcinoma: a case report.

The aim of this article is to extend the knowledge of an unusual presentation of oral syphilis. A 62-year-old man sought evaluation for a severely painful, deeply ulcerated lesion on the floor of the mouth. Two previous oral biopsies revealed nonspecific ulceration with inflammation. Despite these inconclusive results, a head and neck surgeon had advocated resection of the floor of the mouth due to a high suspicion for malignancy. One month after the outbreak of the oral ulceration, the patient developed a widespread cutaneous rash. Cutaneous biopsy and serologic studies confirmed a diagnosis of syphilis. The patient was subsequently treated with a 30-day regimen of oral doxycycline due to a penicillin allergy. At a 3-week follow-up, there was nearly complete resolution of the oral and cutaneous lesions. Early recognition and establishment of a correct diagnosis of syphilis may lead to timely pharmaceutical intervention, avoidance of unnecessary surgical intervention, improved patient outcomes, and reduction of disease transmission.